[klibc] [PATCH klibc 4/4] ipconfig: Use separate sockets for DHCP from multiple interfaces
Ben Hutchings
ben at decadent.org.uk
Sun Dec 31 08:07:44 PST 2017
From: Jay Vosburgh <jay.vosburgh at canonical.com>
Previously ipconfig would use a single multiplexed packet socket to listen
for DHCP responses on multiple interfaces. This fails if the interface that
responds is not the first one enumerated by the kernel, because ipconfig
looks for responses in interface order and is throwing them away if they're
not a proper match.
Fix this by using a separate socket for each interface so that each response
is processed in a correct context.
References: https://bugs.debian.org/852480
References: https://bugs.launchpad.net/bugs/1652348
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
---
usr/kinit/ipconfig/main.c | 53 ++++++++++++++++++++++++++-------------------
usr/kinit/ipconfig/netdev.h | 1 +
usr/kinit/ipconfig/packet.c | 39 +++++++++++++++++++--------------
usr/kinit/ipconfig/packet.h | 4 ++--
4 files changed, 57 insertions(+), 40 deletions(-)
diff --git a/usr/kinit/ipconfig/main.c b/usr/kinit/ipconfig/main.c
index 7be2a1fcb5af..e00f049173fb 100644
--- a/usr/kinit/ipconfig/main.c
+++ b/usr/kinit/ipconfig/main.c
@@ -30,6 +30,7 @@ static unsigned int default_caps = CAP_DHCP | CAP_BOOTP | CAP_RARP;
static int loop_timeout = -1;
static int configured;
static int bringup_first = 0;
+static int n_devices = 0;
/* DHCP vendor class identifier */
char vendor_class_identifier[260];
@@ -220,6 +221,7 @@ static void complete_device(struct netdev *dev)
configure_device(dev);
dump_device_config(dev);
print_device_config(dev);
+ packet_close(dev);
++configured;
@@ -374,34 +376,35 @@ struct netdev *ifaces;
* 0 = No dhcp/bootp packet was received
* 1 = A packet was received and handled
*/
-static int do_pkt_recv(int pkt_fd, time_t now)
+static int do_pkt_recv(int nr, struct pollfd *fds, time_t now)
{
- int ret = 0;
+ int i, ret = 0;
struct state *s;
- for (s = slist; s; s = s->next)
- ret |= process_receive_event(s, now);
+ for (i = 0, s = slist; s && nr; s = s->next, i++) {
+ if (fds[i].revents & POLLRDNORM) {
+ ret |= process_receive_event(s, now);
+ nr--;
+ }
+ }
return ret;
}
static int loop(void)
{
-#define NR_FDS 1
- struct pollfd fds[NR_FDS];
+ struct pollfd *fds;
struct state *s;
- int pkt_fd;
- int nr = 0, rc = 0;
+ int i, nr = 0, rc = 0;
struct timeval now, prev;
time_t start;
- pkt_fd = packet_open();
- if (pkt_fd == -1) {
- perror("packet_open");
- return -1;
+ fds = malloc(sizeof(struct pollfd) * n_devices);
+ if (!fds) {
+ fprintf(stderr, "malloc failed\n");
+ goto bail;
}
- fds[0].fd = pkt_fd;
- fds[0].events = POLLRDNORM;
+ memset(fds, 0, sizeof(*fds));
gettimeofday(&now, NULL);
start = now.tv_sec;
@@ -412,9 +415,12 @@ static int loop(void)
int timeout_ms;
int x;
- for (s = slist; s; s = s->next) {
+ for (i = 0, s = slist; s; s = s->next, i++) {
dprintf("%s: state = %d\n", s->dev->name, s->state);
+ fds[i].fd = s->dev->pkt_fd;
+ fds[i].events = POLLRDNORM;
+
if (s->state == DEVST_COMPLETE) {
done++;
continue;
@@ -442,14 +448,12 @@ static int loop(void)
if (timeout_ms <= 0)
timeout_ms = 100;
- nr = poll(fds, NR_FDS, timeout_ms);
+ nr = poll(fds, n_devices, timeout_ms);
prev = now;
gettimeofday(&now, NULL);
- if ((nr > 0) && (fds[0].revents & POLLRDNORM)) {
- if (do_pkt_recv(pkt_fd, now.tv_sec) == 1)
- break;
- }
+ if ((nr > 0) && do_pkt_recv(nr, fds, now.tv_sec))
+ break;
if (loop_timeout >= 0 &&
now.tv_sec - start >= loop_timeout) {
@@ -468,8 +472,8 @@ static int loop(void)
}
}
bail:
- packet_close();
-
+ if (fds)
+ free(fds);
return rc;
}
@@ -498,6 +502,8 @@ static int add_one_dev(struct netdev *dev)
state->next = slist;
slist = state;
+ n_devices++;
+
return 0;
}
@@ -675,6 +681,9 @@ static struct netdev *add_device(const char *info)
if (bootp_init_if(dev) == -1)
goto bail;
+ if (packet_open(dev) == -1)
+ goto bail;
+
printf("IP-Config: %s hardware address", dev->name);
for (i = 0; i < dev->hwlen; i++)
printf("%c%02x", i == 0 ? ' ' : ':', dev->hwaddr[i]);
diff --git a/usr/kinit/ipconfig/netdev.h b/usr/kinit/ipconfig/netdev.h
index cd853b6c078b..4b75a65ad067 100644
--- a/usr/kinit/ipconfig/netdev.h
+++ b/usr/kinit/ipconfig/netdev.h
@@ -45,6 +45,7 @@ struct netdev {
char filename[FNLEN]; /* filename */
char *domainsearch; /* decoded, NULL or malloc-ed */
long uptime; /* when complete configuration */
+ int pkt_fd; /* packet socket for this interface */
struct netdev *next; /* next configured i/f */
};
diff --git a/usr/kinit/ipconfig/packet.c b/usr/kinit/ipconfig/packet.c
index 446073aba2ae..200180109f2d 100644
--- a/usr/kinit/ipconfig/packet.c
+++ b/usr/kinit/ipconfig/packet.c
@@ -1,3 +1,4 @@
+#include <errno.h>/*XXX*/
/*
* Packet socket handling glue.
*/
@@ -20,17 +21,13 @@
#include "netdev.h"
#include "packet.h"
-static int pkt_fd = -1;
-
uint16_t cfg_local_port = LOCAL_PORT;
uint16_t cfg_remote_port = REMOTE_PORT;
-int packet_open(void)
+int packet_open(struct netdev *dev)
{
- int fd, one = 1;
-
- if (pkt_fd != -1)
- return pkt_fd;
+ struct sockaddr_ll sll;
+ int fd, rv, one = 1;
/*
* Get a PACKET socket for IP traffic.
@@ -48,18 +45,28 @@ int packet_open(void)
sizeof(one)) == -1) {
perror("SO_BROADCAST");
close(fd);
- fd = -1;
+ return -1;
}
- pkt_fd = fd;
+ memset(&sll, 0, sizeof(sll));
+ sll.sll_family = AF_PACKET;
+ sll.sll_ifindex = dev->ifindex;
+
+ rv = bind(fd, (struct sockaddr *)&sll, sizeof(sll));
+ if (-1 == rv) {
+ perror("bind");
+ close(fd);
+ return -1;
+ }
+ dev->pkt_fd = fd;
return fd;
}
-void packet_close(void)
+void packet_close(struct netdev *dev)
{
- close(pkt_fd);
- pkt_fd = -1;
+ close(dev->pkt_fd);
+ dev->pkt_fd = -1;
}
static unsigned int ip_checksum(uint16_t *hdr, int len)
@@ -163,7 +170,7 @@ int packet_send(struct netdev *dev, struct iovec *iov, int iov_len)
dprintf("\n bytes %d\n", len);
- return sendmsg(pkt_fd, &msg, 0);
+ return sendmsg(dev->pkt_fd, &msg, 0);
}
void packet_discard(struct netdev *dev)
@@ -174,7 +181,7 @@ void packet_discard(struct netdev *dev)
sll.sll_ifindex = dev->ifindex;
- recvfrom(pkt_fd, &iph, sizeof(iph), 0,
+ recvfrom(dev->pkt_fd, &iph, sizeof(iph), 0,
(struct sockaddr *)&sll, &sllen);
}
@@ -207,7 +214,7 @@ int packet_recv(struct netdev *dev, struct iovec *iov, int iov_len)
msg.msg_name = &sll;
msg.msg_namelen = sllen;
- ret = recvfrom(pkt_fd, &iph, sizeof(struct iphdr),
+ ret = recvfrom(dev->pkt_fd, &iph, sizeof(struct iphdr),
MSG_PEEK, (struct sockaddr *)&sll, &sllen);
if (ret == -1)
return -1;
@@ -226,7 +233,7 @@ int packet_recv(struct netdev *dev, struct iovec *iov, int iov_len)
iov[0].iov_base = ip;
iov[0].iov_len = iphl + sizeof(struct udphdr);
- ret = recvmsg(pkt_fd, &msg, 0);
+ ret = recvmsg(dev->pkt_fd, &msg, 0);
if (ret == -1)
goto free_pkt;
diff --git a/usr/kinit/ipconfig/packet.h b/usr/kinit/ipconfig/packet.h
index f6cef5210958..4367efe1428e 100644
--- a/usr/kinit/ipconfig/packet.h
+++ b/usr/kinit/ipconfig/packet.h
@@ -3,8 +3,8 @@
struct iovec;
-int packet_open(void);
-void packet_close(void);
+int packet_open(struct netdev *dev);
+void packet_close(struct netdev *dev);
int packet_send(struct netdev *dev, struct iovec *iov, int iov_len);
void packet_discard(struct netdev *dev);
int packet_recv(struct netdev *dev, struct iovec *iov, int iov_len);
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